Kabul ? President Hamid Karzai has extended his lead over his top challenger in Afghanistan’s presidential election under the latest vote results released but remains short of the 50 percent he needs to avoid a two-man runoff.

Afghan election officials are slowly releasing results from last week’s presidential election, and final certified results will not be ready until at least mid-September, after dozens of serious complaints of fraud have been investigated.

Low voter turnout and the fraud allegations have cast a pall over the vote, seen as critical to efforts to stabilize the country, which is wracked by Taliban insurgents and doubts over its fragile democracy. Top challenger Abdullah Abdullah has accused Karzai of widespread rigging, including ballot stuffing and voter intimidation, claims that Karzai’s camp has denied.